1. Field of the Invention
The present invention relates to apparatus and method for dispensing felt tabs in conjunction with operating a nailing gun. One felt tab is held directly beneath the gun so that the operation of driving a nail simultaneously causes one felt tab to be penetrated and thereby pinned by the nail. The principal application of the invention is in the field of building construction, and more particularly, in assembly of roofing materials to roofs.
2. Description of the Prior Art
Roofs are typically constructed by installing weather resistant elements such as tar paper and roofing shingles on a supporting structural stratum such as plywood. Throughout most of the United States, these materials may be installed employing roofing nails and staples. Roofing nails are relatively short, broad headed nails. Staples, if employed, are of the type having a U-shape providing a relatively broad central member which bears against the article being fastened in a manner corresponding to that provided by the broad head of a roofing nail.
In certain parts of the United States, particularly those located where hurricanes and similar severe weather conditions are prevalent, building codes require that the surface area of the roofing material contacted by the nail be extended by provision of a felt tab. Felt tabs are so called because they typically lie on and secure felt or tar paper to the structural element of the roof. Conventional tabs are typically circular, and offer surface area considerably greater than that of the head of a roofing nail and the central member of a staple. When the roofing nail or staple is driven through the tab, a correspondingly greater area of the roof is securely engaged by the combined nail or staple and felt tab. The benefit of this process is similar in principal to that provided by placing a large flat washer beneath the head of a bolt or nail.
In traditional practice, felt tabs have been manually placed beneath a nailing gun. When the gun is fired, or operated, the felt tab is installed simultaneously with the roofing nail. This practice entails obvious hazards to the installer, and also is cumbersome and inefficient. Accordingly, the prior art has developed apparatus for automating feeding and placing of circular felt tabs beneath a nailing gun. The apparatus is attached to the gun, and causes one felt tab to be installed as the gun is operated.
This approach is shown in U.S. Pat. No. 5,067,865 and 5,184,752, issued to Karl H. Zylka et al. on Nov. 26, 1991, and Feb. 9, 1993, respectively. However, both apparatus and method of Zylka et al. differ from those of the present invention. Zylka et al. employs conventional, unconnected disc shaped tabs vertically stacked in a column. By contrast, the present invention employs a coil of detachably connected tabs. The novel apparatus unwinds the coil of tabs such that the tab located at the end of the coil is located directly beneath the path of the next nail or staple to be driven. Apparatus for unwinding a coil is obviously different from that appropriate for dispensing individual discs from a stack of unattached discs. In a further difference, the felt tabs themselves differ from the traditional disc configuration of felt tabs. The novel tabs are generally rectangular, attach to one another by thin, frangible joints, and have depressions formed in their broad faces for receiving prongs of drive apparatus employed to advance the coil.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.